Question

I am trying to debug a problem where our program crashes (segfault) in the ´addToOurSet` method below:

class SomeClass {
    // ( ... )
    void addToOurSet(SomeOtherClass* obj) { ourSet.insert(obj); }
    std::set<SomeOtherClass*> ourSet;
};

The crash is hard to reproduce due to (among other things, the complexity and large data size involved, and failure to reproduce in a debug build; the above example is obviously highly simplified). The traceback shows the crash occurring in:

std::_Rb_tree<...>::insert_unique(SomeOtherClass* const&)

My question is: What could cause the ourSet.insert(...) method to crash? As far as I understand, there is nothing with the inserted object itself that could cause it, since it is a pointer. Correct? So am I looking at a problem with the set itself? Obviously, if the set pointer is invalid for some reason, the call could crash, but could for example some operation on the set cause it to be invalid in this way (like for example deleting past its end or something that is forbidden)?

Answer 1

There are several possibilities:

1. The set itself is invalid (the enclosing SomeClass instance has been deleted, or is being accessed through a dangling pointer etc).
2. There’s a memory corruption somewhere.

I’d probably start with valgrind or a similar tool.